Arrangements and method for hierarchical resource management in a layered network architecture

ABSTRACT

A data network, method and a computer program product, wherein the data network is implemented by a first network level ( 104 ) having a first addressing scheme and at least a second network level ( 108 ) having a second addressing scheme. Each network level provides connectivity over at least one network domain. A first group of Network Resource Managers, NRMs, (b-d)) is arranged to control the resources of the first network level and a second group of NRMs (e-g) is arranged to control the resources of the second network level. The NRMs of the first group (b-d) and second group (e-g) exchange resource requests by using the first addressing scheme and the NRMs (e-g) of the second group perform an address mapping between the first and second addressing schemes.

FIELD OF THE INVENTION

The present invention relates to a data network, a method and a computerprogram product. In particular, the present invention relates toresource management in a data network having a layered networkarchitecture.

BACKGROUND

A current networking trend is to provide “IP all the way” to wired andwireless units. Some objectives are to simplify the infrastructure, tosupport a wide range of applications, and to support diverse userdemands on the communication service. A consequence of this is that theheterogeneity of the IP networks increases, both from a businessperspective and from a technical perspective. From a businessperspective, some providers offer services for particular applicationsegments without having their own network infrastructure. Instead theyoperate overlay networks by acquiring transmission capacity from IPnetwork providers. An overlay network is a logical layer four servicenetwork running on top of a real IP network. From a technicalperspective, having IP as the general-purpose network layer, the rangeof used link layer technologies is increased.

A design trade-off made to enable interconnection was to support onlybest-effort service at the network level. Best-effort service providesadequate support for traditional data applications that can toleratedelay, loss and varying throughput along the path. However, in networkscarrying high loads of traffic, this type of service is often inadequatefor meeting the demands of applications that are more sensitive topacket loss and delay e.g. telephony, video on demand, multimediaconferencing, etc. It is also insufficient to separate the services forpriority businesses.

One trend is to simplify the infrastructure by running all kinds ofapplications and support all kinds of customers, with various networkservice demands, in the same logical IP network i.e. the Internet. Thismeans that IP becomes the unifying communication technology i.e., thenetwork layer. Consequently the environment in which IP must operatebecomes more heterogeneous in the following aspects: the applicationheterogeneity in IP networks is increasing, the link layer heterogeneityis increasing, including Asynchronous Transfer Mode (ATM), MultiprotocolLabel Switching (MPLS), Local Area Network (LAN), Virtual LAN (VLAN),Wireless LAN (WLAN), Global Service Mobile (GSM), Universal MobileTelephony System (UMTS), etc, the user community is becoming moreheterogeneous in terms of service expectations and willingness to payfor the service e.g. professional users and home entertainment users,and the business range is becoming more diverse including a mixture ofnetwork providers and service providers that specialise on differentoverlay services and peer-to-peer applications.

All these trends point towards the Internet becoming a ubiquitousmulti-service network. Consequently, there are strong commercial reasonsfor service providers, network operators and equipment providers tooffer unified solutions for ensured Quality-of-Service (QoS) in IPnetworks.

There are several challenges in providing end-to-end services over an IPnetwork spanning various kinds of link layer technologies: a) IP routersand link layer switching devices should be kept simple and not beburdened with additional processing or signalling functionality. b) Thelink layers may have a vast range of build-in functionality for servicemanagement that should be interfaced e.g., ATM and 3G wireless hasplenty of functionality, while LAN and WLAN has very little. c) Theservices must be able to manage in a uniform way by the networkoperators, both at IP level and inside particular link-layer networks.d) The services must be transitively ensured in a hierarchy of businessoverlays as well as over a chain of peer providers co-operating to offerparticular services.

The entity performing dynamic service management in a provisionednetwork is here called a Network Resource Manager (NRM) (other commonlyused terms for this entity are bandwidth broker, bandwidth manager,network resource controller, network agent, etc.). This entity keepstrack of available resources and performs admission control on incomingrequests for resources from clients. To perform admission control theNRM stores a history of previously admitted resource reservations. TheNRM manager takes decisions to admit new requests for resources based onthe total amount of available resources, the amount currently reservedby previously reservations and the amount of resources requested. Theresources may or may not be scheduled over time.

There are specific requirements for resource management mechanisms. Toprovide service to end users, they must be aware of network resourcesand may schedule them for the committed service at any granularity e.g.for a port range, for aggregate traffic between a pair of subnets, etc.There are currently very few known specifications and implementations ofNRMs. Only some of them handle reservations involving multiple domains,i.e. inter-domain reservations between peering network operators. Theseare described below. None of them handle the heterogeneous andhierarchical aspects of specific link-layers and overlay networks.

In Olov Schelén, “Quality of Service Agents in the Internet”, DoctoralThesis, Department of Computer Science and Electrical Engineering,Division of Computer Communication, Luleå University of Technology,Luleå, 1998 an NRM is described that handles resource management on theIP-level, intra-domain and inter-domain, through peering. It includes IPtopology awareness, admission control, resource scheduling over time andaggregation towards destination domains. It is a pure IP network layersolution that does not handle specific link layer solutions orhierarchies of service providers.

P. Pan, E. Hahne, and H. Schulzrinne have developed a protocol calledBorder Gateway Resource Protocol (BGRP). They aggregate reservationswith the same destination in the border router in the source domain.This solution is focused on IP-level inter-domain resource managementfor IP network operators, running Border Gateway Protocol (BGP).

The QBone Signaling workgroup has specified a protocol for inter-domainQoS signalling called SIBBS. The concept relies on signalling eachreservation request hop by hop between instances of NRMs. End-to-endadmission control is provided with some limited aggregation. In V.Sander et al, “End-to-End Provision of Policy Information for NetworkQoS”, The University of Chicago, inter-domain reservations andsignalling between different resource managers are discussed and twomodels of signalling is primarily discussed.

There are a number of projects that have designed architectures forservice management. One of these projects is Cadenus [IST Cadenus:Creation and Deployment of End-User Services in Premium IP networks]. Inthe Cadenus model, disclosed in O. Dugeon, A. Diakonescu: “From SLA toSLS up to QoS control: The CADENUS Framework”, WTC'2002,http://www.cadenus.org/papers, there are units for access mediation,service mediation, resource mediation, and network control. The ResourceMediation component resembles what is denoted as NRM in thisspecification.

Drafts disclosed in IETF Next Step In Signaling (NSIS) working group:http://www.ietf.org are primarily focused on path-coupled signallinghop-by-hop between signalling aware routers. One proposal, named CASP,is claimed to provide also path-decoupled signalling that possibly couldbe used between instances of NRMs.

For RSVP-based signalling, which is router centric and stateful, therehas been a proposal for a Subnet Bandwidth Manager (SBM) to handleresource management in one specific link layer technology known as 802.xLANs described in R. Yavatkar et al. “SBM (Subnet Bandwidth Manager): AProtocol for RSVP-based Admission Control over IEEE 802-style networks”.IETF. RFC 2814.

The technologies described above, except SBM and CADENUS, focus onresource management at the IP network layer only. All proposals arequite static in supporting hierarchical resource management for specificlink-layers. In the case of Cadenus, there is a technology dependentNetwork Controller that can handle particular link-layer technologies.In the case of SBM, it acts as a black-box admission controller for RSVPlike signalling to provide admission control inside a particular kind oflink layer network. This provides a solution only for IEEE 802 linklayer technologies.

Thus the proposed solutions provide either single level IP resourcemanagement or strict link-level resource management. This means thatnone of these solutions provide uniform resource management for theunifying communication technology that IP network layer has become i.e.,including various applications and overlay networks as well as differentlink layer technologies. More specifically, the proposed solutions havethe following drawbacks:

-   -   None of the proposed solutions provide uniform service        management for hierarchies of customers and providers i.e.,        overlay network service providers, Virtual Private Networks        (VPNs), Enterprises, etc. being customers to different networks        operators.    -   They do not provide a general model for handling resources in        hierarchies of link layer solutions, allowing some solutions to        use internal support for resource management and providing other        solutions with full support for network resource management at        particular sub-levels of IP.    -   Service management is complicated from an operator's point of        view because separate tools/views are needed to manage different        link layer technologies.    -   End-to-end services can not be provided effectively because the        admission control architecture does not connect IP network layer        resources and link layers specific resources seamlessly.    -   No automated services through self management by customers can        be offered since there is no unified solution for service        invocation over the different protocol layers i.e., the IP        network layer and underlying link layers.

In addition to the above mentioned drawbacks, the proposed solutionshave the following limitations:

-   -   Network operators obtain little feedback on the booking levels,        currently and over time, in networks and sub-networks since the        proposed solutions do not support synchronized and unified        scheduling of resources at both these layers.    -   For link layer management, current solutions do no clearly        separate the functions for sub-network control such as control        of a domain with devices and functions for device control such        as control of specific devices. Consequently, adding support for        new devices is cumbersome since that may affect the functions        for sub-network control.

SUMMARY OF THE INVENTION

In heterogeneous environment, providers in hierarchies at variousbusiness levels need to cooperate and ensure services between eachother. Moreover, subnets inside the IP network are link-layer topologiesthat have various levels of built-in management functionality. To offera uniform, consistent and seamless view for service management in suchheterogeneous IP networks, there is a need for scalable solutions fordynamic resource management supporting various kinds of overlay networksand link-layer technologies. As mentioned above the prior art solutionsprovide either a single level IP resource management or strictlink-level resource management, which implies that it is neitherpossible to have a uniform service management nor a general resourcemanagement for different layers.

Thus, the object of the present invention is to provide a generalresource management extending different protocol layers.

The data network according to the present invention, comprising a firstgroup of Network Resource Managers, NRMs, arranged to control theresources of the first network level and a second group of NRMs arrangedto control the resources of the second network level, wherein the NRMsof the first group and second group comprise means for exchangingresource requests by using the first addressing scheme, and wherein theNRMs of the second group further comprise means for performing anaddress mapping between the first and second addressing schemes, makesit possible to provide a general resource management extending differentprotocol layers.

The method according to the present invention, comprising the steps ofcontrolling the resources of the first network level by a first group ofNetwork Resource Managers, NRMs, and controlling the resources of thesecond network level by a second group of NRMs, exchanging resourcerequests between NRMs of the first and second group by using the firstaddressing scheme, and performing an address mapping between the firstand second addressing schemes, makes it possible to provide a generalresource management extending different protocol layers.

Thus, the arrangements and method according to the present inventionmake it possible to provide feedback to network operators on bookinglevels, current and over time, in networks and sub-networks. This isenabled through synchronized and unified scheduling of resources at boththese layers. The information may be provided in uniform graphs at allnetwork levels.

Furthermore, the arrangements and method enables automated servicesthrough self-management by customers by offering a unified solution forservice invocation covering both the IP network layer and underlyinglink layers. Such a unified solution for service invocation considerablyreduce the complexity in allowing customers to self-manage their networkaccesses, service providers to self-manage their booked resources, andnetwork operators to effectively provide transport of data.

An advantage with the present invention is that the proposed solutionallows flexible extension of IP networks with new link-layer solutionsand virtual service operators while still providing a unified model formanagement of services and resources across those of the IP and the linklayers. The solution is applicable in individual network domains, overseveral link technologies, across several IP routing domains (autonomoussystems), across several layers of service providers etc.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of the network architecture accordingto the present invention.

FIG. 2 is a flowchart of the method according to the present invention.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. In thedrawings, like numbers refer to like elements.

A data network, a method and a computer program product according to thepresent invention may be implemented in a conventional data networkimplemented by at least a first 104 and a second 108 logical networklevel.

An example of such a conventional network is a multi-technology networkwhere an operator provides an IP/MPLS backbone and several accessnetworks based on various switched link layer technologies e.g.,including an access network based on ATM switching, another accessnetwork based on Ethernet switching and a third based on WLANtechnologies. Moreover, the network may comprise interconnectablerouters, servers and other network elements known by a man skilled inthe art.

In this application, a data network is defined as a switched networkforwarding data units between network interfaces of network nodes usingidentifiers associated with the target circuit being setup through thenetwork e.g., as in Asynchronous Transfer Mode (ATM networks and inMultiprotocol Label Switching (MPLS) networks, or a datagram networkforwarding data units between network interfaces of network nodes usingglobal addresses enabling local next-hop decisions made by each nodee.g., as in Internet Protocol (IP) networks. The data units may be offixed size e.g., ATM cells or of variable size e.g., IP packets usingtheir destination addresses for datagram forwarding or using MPLS tagsfor switching.

The two levels mentioned above is a first 104 and second 108 networklayer. In one embodiment of the present invention, the first networklayer 104 is an IP layer and the second network layer 108 is a linklayer. In another embodiment of the present invention, the first networklayer is an IP layer 106 and the second network layer is a second IPlayer or higher protocol layer, i.e. a protocol layer on top of the IPlayer such as a transport protocol layer or an application protocollayer, used to control an overlay network 102. Thus, the overlay networkmay be implemented on a protocol level on top of the IP layer or on asecond IP layer but using different addressing schemes from the first IPlayer. When the overlay network is implemented on the second IP layer,the set of IP addresses of the overlay network is separated from theremaining IP address of the IP layer and when the overlay network isimplemented on a protocol layer on top of the IP layer, separated setsof addresses are obtained automatically. The overlay network comprises anumber of end-hosts, i.e. servers that may communicate end-to-end, e.g.peer-to-peer to offer a common service. There may be several levels ofoverlay networks which then results in a hierarchy of NRMs managingresources in these networks.

The data network, method and computer program product of the presentinvention require that the network comprises means for eitherimplementing a single admission controlled forwarding class, orimplementing forwarding classes differentiated or separated on packet orframe level where one or more traffic classes are subject to admissioncontrol.

The data network according to the present invention illustrated in FIG.1 is implemented by a first network level 104 having a first addressingscheme and at least a second network level 108 having a secondaddressing scheme. Each network level provides connectivity over atleast one network domain e.g., a routing domain, a provider networkcontaining a number of private routing domains, an overlay network, alink layer subnet, or a part of a link layer subnet. A first group ofNRMs b-d is arranged to control the resources of the first network level104 and a second group of NRMs e-g is arranged to control the resourcesof the second network level 108, wherein the NRMs of the first group b-dand second group e-g comprise means for exchanging resource requests byusing the first addressing scheme, and the NRMs of the second group e-gfurther comprise means for performing an address mapping between thefirst and second addressing schemes.

Two network levels i.e. a first and a second level may also beimplemented by using the same protocol layer e.g. IP. A group of NRMs isthen arranged to control the resources of each of these levels. Theaddresses used at these levels will be of the same type e.g. IPaddresses but without a fixed mapping between these sets of addresses.The NRMs of the second group comprises means for performing an addressmapping between the first and second addressing sets. E.g., the secondnetwork level may be a VLAN i.e. an overlay network carrying trafficwith non-public IP addresses over the first network level that may be anIP network using public IP addresses.

The data network according to embodiments of the present inventioncomprises further:

-   -   A third network level 102 having a third addressing scheme, the        resources of the third network level 102 is controlled by a        third group of NRMs a. The third group of NRMs a comprises means        for exchanging resource requests with NRMs of the first network        level using the first addressing scheme. The NRMs of the third        group comprise in accordance with one embodiment of the present        invention means for performing a mapping between the third        addressing scheme and the first addressing scheme. The third        network level is, when the second network layer is a link        protocol layer, according to one embodiment of the invention an        IP layer or higher protocol layer, i.e. a protocol layer on top        of the IP layer such as a transport protocol layer or an        application protocol layer, used to control an overlay network.        Thus, the overlay network may be implemented on a protocol level        on top of the IP layer or on a second IP layer but using        different addressing schemes from the first IP layer as        mentioned above. In accordance with a further embodiment of the        present invention, the third network level is a link protocol        layer provided that the second network level is an overlay        network.    -   One single logically centralised Network Resource Manager (NRM)        for each network, e.g. for each IP routing domain i.e.        Autonomous System (AS), for each link layer subnet, or for each        overlay network. NRMs at AS-level may inter-operate through        peering in a distributed fashion. The single logically        centralised NRM may be distributed or backed up over several        physical servers. Moreover, the logically centralised NRM may be        a super- or sub-NRM that are defined below.    -   A hierarchy of sub-NRMs. A sub-NRM operates under one super-NRM        and is responsible for a particular network sub-domain e.g., a        network area of the super-domain. Those NRMs may have other        sub-NRMs. A network area also known as routing area is a part of        a routing domain where the topology is opaque to the rest of the        domain. Note that a subnet-NRM always is a sub-NRM to a        super-NRM, while a sub-NRM does not need to be a subnet-NRM.        Also, there can be several levels of NRMs in a subnet, which        means that a subnet-NRM can be a super-NRM to lower level        subnet-NRMs (i.e., sub-NRMs to this super-NRM).    -   A Network Controller (NC) or a hierarchy of NCs for controlling        or probing particular network sub-domains e.g., network areas of        a super-domain. The network controller is a slave of an NRM and        they do not implement resource management such as admission        control. Instead, the NC serves an NRM by either probing a        network domain for information or by injecting information into        a domain.    -   One or many Device Controllers (DCs) for controlling particular        network devices. DCs contain vendor specific interfaces and        drivers. Each DC may interface with several devices of the same        kind.

It should be noted that the NCs and DCs are not required if the NRM isused only as a decision support system. I.e., when the NRM is not usedto reserve resources in the network. However, clients e.g., applicationsor overlay networks register their network usage with the NRM e.g. tocollect information needed to upgrade the network to meet demands of theclients.

The entities in the architecture are related as directed graphs as shownin FIG. 1. Note that peering between siblings at each layer may occur tosolve certain problems efficiently (as in FIG. 1 between MRM b and h andbetween NRM d and i). This may be exemplified by two adjacent link layernetworks that are interconnected through several links or networkinterfaces. The NRMs in these networks may then need to peer with eachother to distribute the load between the multiple interconnections.

As stated above, the functionality of an NRM is characterised byresource management capabilities for a given network domain e.g., arouting domain, a provider network containing a number of privaterouting domains, an overlay network, a link layer subnet, or a part of alink layer subnet. The NRM comprises means for keeping track ofavailable resources inside its domain, including topology link resourcesand service commitments. Moreover, it comprises means for performingadmission control for its domain in order to provide services tocustomers/clients. The topology managed by an NRM in a virtual overlaynetwork or in a VPN may contain some clouds of unknown “real” topology.The topology managed by an NRM may also have a real topology of routersor switches. Thus, the NRM controls the real topology of routers orswitches except in the overlay network case. According to the presentinvention, NRMs in real networks manage resources in IP level topologiesand NRMs in subnets manage resources in link-layer subnet topologies.Note that there may be several levels of each kind of NRM managing therespective layer. To denote the entities forming a parent-childrelation, the terms super-NRM and sub-NRM are used in thisspecification.

Consequently, the functionality of the NRMs is basically the sameindependently whether the NRM is managing the link layer, i.e. asubnet-NRM, or the IP layer in terms of capabilities for resourcemanagement in accordance with the present invention. The difference liesin their responsibilities and communication relations with otherentities. The responsibility of a subnet-NRM is resource managementincluding topology awareness and path-sensitive admission control for aspecific subnet. A subnet, also denoted sub-network, is an IP networkwhere all nodes can be reached directly with link layer, i.e. layer two,addressing/switching. In the routing table of all IP-nodes in a subnetthere is normally a subnet mask, IP-prefix, matching the IP addressesfor all nodes in that subnet, indicating that IP-packets can be sentdirectly to those nodes using the link layer addressing.

According to the present invention, the interface for making resourcerequests with an NRM is based on IP addresses independently of at whichlevel the NRM is operating. By this, the present invention provides auniform service management. A subnet-NRM managing a switched link layertopology using a different addressing scheme than the IP address isaccording to the present invention responsible for maintaining themapping between a super-address and a sub-address that is associatedwith a super-address. A super-address may be an IP address and thesub-address may be a physical address for nodes in the subnet that aregiven a super-address e.g., edge nodes of the subnet such as a BroadbandRemote Access Server (BRAS) in a Digital Subscriber Line (DSL) accessnetwork and internal nodes such as a Digital Subscriber Line AccessMultiplexer (DSLAM) in a DSL network. This allows the super-NRM torequest resources through and in the domain of a sub-NRM by justindicating the nodes between which resources is requested using its ownaddress scheme.

According to one embodiment of the present invention, the sub-NRM isadapted to obtain the mapping between sub-addresses and super-addressesthrough NCs and DCs, respectively, which comprise means for probingdevices such as Dynamic Host Configuration Protocol (DHCP) servers andOperational Support Systems (OSSes), or listening to signalling inestablishing address mappings such as DHCP messages exchanged between aDHCP server and a client at a node in the subnet. The mapping betweenaddresses can also be made by a super-NRM if it uses an addressingscheme different from IP. E.g., some overlay networks may use their ownaddressing schemes. Then, the super-NRM comprises means for obtainingmapping information similar to the means of the sub-NRMs for obtainingtheir mapping information.

Note that there may be cases when a sub-NRM manages a subnet or anetwork area that uses the same addressing scheme as its super-NRM.E.g., an overlay network may use the same addressing scheme as thenetwork it uses to obtain connectivity between its nodes.

The implementation of any logically centralised NRM may be clustered orotherwise physically distributed according to embodiments of the presentinvention.

Each NRM may interact with a number of clients that try to connect toit. Control of whether particular clients are allowed to connect isperformed through authentication. Control of their privileges is ensuredthrough policies. The clients may be other entities that like to requestresources e.g., peering NRMs, systems such call managers for Voice overIP (VoIP), overlay networks, applications such as video conferencesystems, etc. In addition, the clients may be entities that provideservices that are vital to the operation of the NRM, such as sub-NRMsthat provide resource management in a subnet, NCs that are prepared toprovide information about the network managed by the NRM, etc. Theentities that provide services to an NRM are once connected generallyactivated/controlled from that NRM.

A Network Controller (NCs) performs sub-tasks issued from one or moreNRMs, typically implementing general purpose, i.e. vendor independent,functionality for probing and controlling particular areas of thenetwork (e.g., an IP topology probe collecting a resource map throughstandard routing protocols and management information bases). Accordingto one embodiment of the present invention, there is at least one NC ina domain of an NRM. The NC may be active, e.g. performingconfigurations, passive, e.g. just listening, or a mixture of both. NCsmay process information in order to provide scalable and efficientcommunication with their NRM.

A Device Controller (DC), controlled by one or more NCs, is, inaccordance with the present invention, controlling vendor specific nodetechnologies. Thus, DCs implement vendor-specific drivers. There may beone or many DCs for each NC and each DC may control one or many physicalnodes.

The DCs and the NCs may thus in accordance with one embodiment of thepresent invention be located in the IP and/or in the link layer and/orin the overlay network. Accordingly, the DCs and NCs may hence compriseIP- and/or link layer- and/or overlay network functionality.

The entities NRM, NC and DC communicate using general-purpose protocolsand/or interfaces allowing functionality to be distributed overdifferent devices/processes or to be co-located at one device/process.The protocols are typically implemented through a client server modelwith APIs providing a software interface e.g. shielding the protocoldetails. Each entity may act as both client and server, depending onwhere in the architecture they reside. Thus, the NRMs, NCs and DCs aretypically implemented in software by a computer program product runningon standard hardware.

Typically, but not mandatory, lower level entities inside an AS of anetwork provider register (upwards in FIG. 1) towards their super-NRM ina chain up to the AS-level NRM. A super-NRM may then use the services ofselected sub-NRMs and NCs as if it was a client. Service providers andother customers e.g., enterprises that have their own overlay NRMsconnect as clients (downwards in FIG. 1). Inside an AS, there is onelogically centralised top-level network resource manager. At theinter-AS level, the NRMs communicate between each other according to afully distributed model.

Below, the interaction between entities is described on a conceptuallevel. According to the present invention, there may be one generalprotocol available for any entity/customer requesting resources from anNRM. Customers may be end-hosts, application framework servers, otherNRMs (peering-NRMs i.e. communicating NRMs on the same level,super-NRMs, etc). The present invention provides also support for bothintra-domain requests and inter-domain requests, since the NRM handlesresource requests between two addresses. In the intra-domain case, theNRM itself handles the request when both addresses are within the samedomain. In the inter-domain case, the resources are reserved bycommunicating with a peer-NRM located in another NRM.

Examples of typical parameters, e.g. exchanged, distinguishing aredisclosed below. It should however be noted that other parameters may beused, which is obvious for a man skilled in the art.

Examples of distinguishing parameters of the resource requests are:resources (e.g., bandwidth), source, destination addresses plus optionaladdress masks, optional duration (start time, stop time), and optionalpath specification (e.g. only for some trusted clients).

The NC, that is arranged to act as a client to an NRM, comprises meansfor delivering detailed information, e.g. topology maps, trafficmeasurement information, alarms, etc. of the network domain that iscontrolled by the NRM. The NC may also comprise means for receivingdetailed information on the traffic conditioner to be configured in thenetwork domain. The data exchanged between an NC and an NRC may include:topology maps, traffic measurements, traffic conditioning information,etc.

The DCs are in one embodiment, for efficiency reasons, co-located withNCs but the DCs may also be located separately as well. Interaction withDCs typically includes any kind of information that can be read orwritten from specific devices. Examples of information to be read areinterface speeds and provisioning information, and examples ofinformation to be written are information about traffic conditionersi.e., token bucket shapers.

In the following, various roles for NRMs controlling a specificsub-network domain are explained. Some subnet domain uses technologiesthat have advanced support for resource management e.g., ATM networks.In this case the sub-NRM that handles such a resource aware sub-domainneeds very little functionality. When admission requests are issued froma super-NRM, the sub-NRM simply translates the request (possibly throughaddress mappings and other information obtained from an NC) to beexecuted by e.g. a built-in ATM resource manager. With this solution theATM subnet remains a black box to the sub-NRM. Alternatively, thesub-NRM may maintain a topological database for the ATM subnet (byprobing it) and provide resource management for it.

Certain subnet domains use technologies that have no internal supportfor resource management e.g., switched IEEE 802 networks. In this caseit is advisable to have a sub-NRM that fully controls that resourceun-aware sub-domain. That sub-NRM is arranged to use NCs and DCs locatedin the resource unaware domain to extract the topology of the subnet,perform traffic measurements etc. e.g. in order to provide adequateadmission control.

Some domains use technologies that support mixed topologies i.e., eachrouting topology provides separate routes through the network. In somecases there is no straight hierarchy between these topologies. Instead,they are inter-dependent. An example of this is an IP/MPLS domain, wherethe basic topology may be determined through standard IP link-staterouting protocols (e.g., OSPF, IS-IS) and is then used both for IP-basedrouting and for traffic engineered MPLS-Label Switched Paths (LSPs).Thus, both the IP and MPLS routing topology are based on the same basictopology of nodes and links (subnets). In this case, it is preferred toprovide an NRM that handles resource management both by the IP and MPLSstandard. In this case, at least one NC is responsible for IP routingtopology awareness by using standard routing protocols and at least oneNC is responsible for MPLS routing topology awareness by using DCs usingMPLS MIBs and vendor specific command line interfaces.

The solution according to the present invention solves the above statedproblems by providing a uniform service management for hierarchies ofproviders and customers i.e., network operators, overlay serviceproviders, VPNs, enterprises by having NRMs at all levels using onesingle addressing scheme, e.g. the IP address. Thus, the NRMs provide auniform service interface towards applications and may offer resourcemanagement with uniform addressing at all protocol levels, e.g. the IPlevel and the link level. Furthermore, a uniform service management fromthe operators' point of view is provided, since the NRMs are used at alllevels with the uniform addressing. Thus, separate tools/views fordifferent subnet technologies are avoided.

Providing a general model for handling resources in hierarchies of thelink layer solutions by NRMs at all levels of the link layer where eachsub-NRM provides resource management by using addresses of thesuper-domain. Each NRM may provide different functionality internally,ranging from providing simple mapping to sub-network resource managementtechnology i.e., for sub-networks such as ATM and 3G wireless which haveadvanced resource management functionality built-in to full support fornetwork resource management i.e., for sub-networks such as Ethernet thatmay not have any built-in functionality for resource management. Inaddition, end-to-end QoS is provided effectively because the datanetwork according to the present invention connects the IP network layerresources and the link layer's specific resources seamlessly asdescribed above.

The functions for network control and device control for link layermanagement are separated by using network controllers and devicecontrollers. NCs control a network area as previously defined includingmany devices independent of the devices. DCs control individual devicesusing standard interfaces or vendor specific interfaces. There may be aspecific DC for each kind of device such as routers, switches, trafficconditioning boxes, etc.

The method according to the present invention is applicable in a datanetwork implemented by a first network level having a first addressingscheme and at least a second network level having a second addressingscheme each network level provides connectivity over at least onenetwork domain. The method illustrated in the flowchart in FIG. 2comprises the steps of:

-   201. controlling the resources of the first network level by a first    group of Network Resource Managers, NRMs, and-   202. controlling the resources of the second network level by a    second group of NRMs,-   203. exchanging resource requests between NRMs of the first and    second group by using the first addressing scheme, and-   204. performing an address mapping between the first and second    addressing schemes.

As mentioned above, the functionality of the entities such as NRMs, NCs,and DCs used in the present invention may be implemented by a computerprogram product. The computer program product is directly loadable intothe internal memory of a computer within a router or a server in thedata network according to the present invention, comprising the softwarecode portions for performing the steps of the method according to thepresent invention. The computer program product is further stored on acomputer usable medium, comprising readable program for causing acomputer, within a router or server in the data network according to thepresent invention, to control an execution of the steps of the method ofthe present invention.

In the drawings and specification, there have been disclosed typicalpreferred embodiments of the invention and, although specific terms areemployed, there are used in a generic and descriptive sense only and notfor purposes of limitation, the scope of the invention being set forthin the following claims.

1. A method in a data network implemented by a first network levelhaving a first addressing scheme and at least a second network levelhaving a second addressing scheme, each network level providingconnectivity over at least one network domain, the method comprising thesteps of: controlling resources of the first network level by a firstgroup of Network Resource Managers (NRMs); controlling resources of thesecond network level by a second group of NRMs, wherein the first groupand the second group of NRMs comprise means for communicating on acommon network level; exchanging resource requests between the NRMs ofthe first and second groups using the first addressing scheme, the NRMsof the first group and the second group admitting new resource requestsbased at least in part on a total amount of available resources, anamount of resources currently reserved by previous reservations, and anamount of resources requested in the new resource requests; andperforming an address mapping between the first and second addressingschemes so that a set of resources that is used by a reservation in thesecond group, controlled and known by the second group, is aggregatedinto a single resource in the first group of NRMs.
 2. The methodaccording to claim 1, wherein the first network level is the InternetProtocol (IP) layer.
 3. The method according to claim 2, wherein thesecond network level is a link protocol layer.
 4. The method accordingto claim 2, wherein the second network level is a second IP layercontrolling an overlay network on top of said IP layer.
 5. The methodaccording to claim 2, wherein the second network level is a secondprotocol layer controlling an overlay network on top of the IP layer. 6.The method according to claim 1, wherein the data network furthercomprises a third network level having a third addressing scheme and themethod comprises the further steps of: controlling resources of saidthird network level by a third group of NRMs; and exchanging resourcerequests between any of the NRMs of the first and second network levelsusing the first addressing scheme.
 7. The method according to claim 6,further comprising the step of: performing an address mapping betweenthe first and third addressing schemes.
 8. The method according to claim7, wherein the third network level is a third protocol layer controllingan overlay network on top of the IP layer.
 9. The method according toclaim 7, wherein the third network level is a second IP layercontrolling an overlay network on top of said IP layer.
 10. The methodaccording to claim 7, wherein the third network level is a link protocollayer.
 11. The method according to claim 1, wherein the NRMs within atleast one of said groups are arranged in a hierarchical structurearranged to communicate with each other.
 12. The method according toclaim 1, wherein each of the NRMs is a logically centralized unit in anetwork.
 13. The method according to claim 12, wherein said logicallycentralized unit is distributed or backed up over several physicalservers.
 14. The method according to claim 1, wherein the data networkin at least one of the network levels comprises a Network Controller(NC), wherein the method comprises the further steps of: receiving bythe NC a request from an NRM; and obtaining detailed informationincluding at least one of topology maps, traffic measurementinformation, and alarms of the network domain that is controlled by saidNRM in response to said request.
 15. The method according to claim 14,wherein the data network in at least one of the network levels comprisesa Device Controller (DC), wherein the method further comprises the stepsof: receiving by the DC a request from the NC; and controlling vendorspecific node technologies in response to said request.
 16. The methodaccording to claim 15, wherein the DC is co-located with the NC in theat least one of the network domains.
 17. A computer program productstored on a computer usable medium, comprising readable program forcausing a computer, within a router or a server in the data network tocontrol an execution of the steps of claim 1.